Large 4kv Elliott Air Compressor
I just hope you did not make a typo.,If you say 4 Kilovolts then that part you will have to call a electrician to deal with it there is nothing the DIY can do this part.
But if you say 4 Kilowatts motour then do this part next.,
If so follow KBsparky advise to give us little more infomation.
And the location you are at due the European area the 4KW motor can be either single phase or triphase.
The answer will be based on NEC ( National Electrical code ) or CEC ( Cananda Electrical code ) or ECF ( Electrique Code France )